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<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
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    <title>Document</title>
    <style>
        .big{
            width: 415px;
            height: 400px;
        }
        .small>img{
            width: 100px;
            height: 100px;
        }
    </style>
				<script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.5.1/jquery.js"></script>
</head>
<body>
    <div>
        <img src="./ju.jpg" alt="" class="big">
    </div>
    <div class="small">
        <img src="./ju.jpg" alt="">
        <img src="./ying.jpg" alt="">
        <img src="./hu.jpg" alt="">
        <img src="./bu.jpg" alt="">
    </div>

    <script>
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			$('img').eq(i).mouseover( function () {
				$('img').eq(0).prop('src', $('img').eq(i).attr('src'));
			})
		}

    </script>

</body>
</html>